Experimental and Theoretical Studies of Unevenly Designed 4-bladed Inducers

由于H-II火箭的研制成功，日本在航天工程技术方面已经赶上了美国和欧洲。然而，在H-II、阿丽亚娜-V和航天飞机的涡轮泵诱导器的发展阶段，观察到了旋转空化。因此，旋转空化一直是世界各国普遍存在的问题。在这种情况下，诱导器的设计既要考虑到较高的吸气性能，又要考虑到对旋转空化的抑制。本文研制了不均匀设计的四叶诱导轮，从理论和实验两个方面研究了抑制或避免旋转空化的有效途径。(1)对交替叶片空化和旋转空化进行了理论分析。通过定常分析发现，在一定的空化数范围内，均数空化和交替叶片空化均存在。在这种情况下，通过对…的稳定性分析也发现了它此外，交替叶片空化比偶数长度空化更稳定。此外，将这些分析推广到非均匀设计的四叶片诱导轮的情况，并考察了旋转空化和交替叶片空化的稳定性。(2)按照相同的准则制造了四叶片诱导轮，并为LE-7设计了三叶片诱导轮。另外还研制了一种无后掠的四叶引导器，通过实验对比来检验后掠的效果。此外，还测试了一种叶片间隔为1片的微掠叶片的诱导轮，该诱导轮是在没有后掠的情况下改装而成的。(3)通过对进气压力脉动的混沌分析，研究了进气压力脉动的非线性行为，而文献(1)的理论分析基于线性分析，而文献(2)的实验主要采用傅立叶分析。在这里，我们研究了通过观察相图中的吸引子来获得关于非定常空化的信息的可能性。较少

Owing to the successful development of the H-II Rocket, Japan has caught up with the U.S.A.and Europe in terms of the technology of aerospace engineering. Rotating cavitation, however, was observed in the development stage of the turbopump inducers for H-II,ARIANE V and Space Shuttle. So, the rotating cavitation has been a common problem all over the world. Under such conditions, inducers should be designed by taking into account the higher suction performance but also the suppression of the rotating cavitation. In this study, we manufactured unevenly designed 4-bladed inducers and investigated the effective ways to suppress or avoid the rotating cavitation both theoretically and experimentally.(1) Both the alternate blade cavitation and rotating cavitation were analyzed theoretically. By a steady analysis, it was found that both even length cavitation and alternate blade cavitation do exist in some range of cavitation number. In such a case, it was also found by a stability analysis t … More hat the alternate blade cavitation is more stable than even length cavitation. Moreover, these analyzes were extended for the case of unevenly designed 4-bladed inducers, and the stabilities of rotating cavitation and alternate blade cavitation were examined.(2)A 4-bladed inducer was manufactured along the same guideline with the designment of 3-bladed inducer for LE-7. Another 4-bladed inducer, which has no swept back, was also manufactured to examine the effect of swept back through the comparison of experiments. Moreover, an inducer with slightly swepted blades at 1 blade intervals, which were modified from the inducer without swept back, was tested. It was found that the swept back has an effect on the suppression of both rotating cavitation and alternate blade cavitation.(3) Non-linear behavior was investigated by chaotic analysis of inlet pressure fluctuation, whereas theoretical analyzes in (1) were based on linear analyzes, and mainlyFourier analysis was used in experiments in (2). We herein investigated the possibility to derive the information about the unsteady cavitation by the observation of attracters in the phase portrait. Less